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; ; Isozaki, Kazunori; ; ; Nagai, Akinori;
PNC TN9440 97-009, 435 Pages, 1997/05
On the 8th in December 1995, the secondary sodium leak accident occurred at Prototype Fast Breeder Reactor MONJU. Experimental Fast Reactor JOYO was under the 11th periodical inspection then. Total review of the JOYO plant for check of the sodium leak related equipment, check of manuals, and a practice of disaster prevention for sodium leak, and so on were made to have assurance of plant safety, which was required based on official report of MONJU sodium leak accident. Moreover, we properly improved the equipment and reinvestigated the plant management. As the result of these checks, evaluations and improvements, plant safety for sodium leak and fire was secured, and JOYO was started reactor operation on the 3rd in March 1997 after the confirmation by Science and Technology Agency (STA) and Ibaraki prefecture, and on 24th, JOYO passed the 11th periodical inspection, and began to operate the JOYO plant duty cycle. This report describes about the result of those checks of equipment.
; ; Isozaki, Kazunori; ; ; Nagai, Akinori;
PNC TN9440 97-008, 410 Pages, 1997/05
On the 8th in December 1995, the secondary sodium leak accident occurred at Prototype Fast Breeder Reactor MONJU. Experimental Fast Reactor JOYO was under the 11th periodical inspection then. Total review of the JOYO plant for check of the sodium leak related equipment, check of manuals, and a practice of disaster prevention for sodium leak, and so on were made to have assurance of plant safety, which was required based on official report of MONJU sodium leak accident. Moreover, we properly improved the equipment and reinvestigated the plant management. As the result of these checks, evaluations and improvements, plant safety for sodium leak and fire was secured, and JOYO was started reactor operation on the 3rd in March 1997 after the confirmation by Science and Technology Agency (STA) and Ibaraki prefecture, and on 24th, JOYO passed the 11th periodical inspection, and began to operate the JOYO plant duty cycle. This report describes about those JOYO plant safety for sodium leak and fire protection.
*; *; *; *
PNC TN941 79-114, 38 Pages, 1979/07
Heat load for nitrogen atmosphere cooling system at reactor power of 50MW was proved to be corresponding to the design value of approximately 4.1 
10
Kcal/n which was estimated at the reactor power of 100MW. This report describes the predicted heat loads of the reactor power of 75MW and 100MW, possibility of ability to cool nitrogen atmosphere being increased and performance of the nitrogen atmosphere cooling system. They were obtained with results of dual operation of heat exchangers and refrigirators which was carried out to survey the possibility of ability to cool the nitrogen atmosphere being increased. (1)Predicted heat load at the reactor power of 75MW and 100MW Increasing rates of the heat load against the design value were as follows: [75 MW : approximately 6%] [100 MW : approximately 15%] (2)Possibility of ability to cool the nitrogen atmosphere being increased It is possible to lower a mean temperature of the nitrogen atmosphere with the dual operation of the heat exchangers, which however requires dual operations of the refrigirators and freon circulating pumps. (3)Performance of the nitrogen atmosphere cooling system Overall heat transfer coefficient of the heat exchangers satified its design value, however heat exchanger outlet nitrogen gas temperature was approximately 3
C higher than its design value. This discrepancy of 3C was considered as the evapolation temperature of freon did not satisfy the deaign temperature.
Hirose, Tadashi*; Endo, Masayuki*; Nanashima, Takeshi*; *; *; Yamamoto, Hisashi*
PNC TN941 79-90, 47 Pages, 1978/12
The purposes of this test are to : (1)verify the procedure for decreasing reactor power from 50 MWt to shutdown, (2)remove the decay heat after shutdoun by the main heat-transport system using the normal procedure, (3)confirm that the rate of temperature decrease does not exceed -50C/hr during the cooldown. At the end of a full power (50MWt) run of 100hours, record steady state plant data. By insertion of one regulating rod, decrease reactor power until PRM indicates 80% (40MWt). Verify that a steady-state condition has been achieved (at least 15 minutes) and repeat data recording. Following same procedure, decrease power stepwise to 30 MWt, 20MWt and 10MWt. Stop the DHX Blowers at 10MWt. Decrease reactor power with one regulatiag rod to 1MWt as indicated on IRM, then shut down the reactor by slow scram. By manual operation of DHX vanes and dampers, decrease coolant temperature as rapidly as possible to the "warm standby" condition (The maximum allowable cooldown rate of 50C/hr must not be exceeded). Test results : (1)The main coolant temperature decrease rate averaged 34C/hr (maximum of 48C/hr) during the cooldown from full power to reator shutdown. During this period, the insertion rate of one regulating rod was approx. 1mm/minute. (2)The average rate of main coolant temperature decrease from shut down to "warm standby" was 35C/hr in manual control.
-ray backgroundIshihara, Kohei*; Sakai, Yosuke*; Kawarabayashi, Jun*; Tomita, Hideki*; Naka, Ryuta*; Asada, Takashi*; Morishima, Kunihiro*; Nakamura, Mitsuhiro*; Maeda, Shigetaka; Iguchi, Tetsuo*
no journal, ,
In order to measure neutron spectrum in high -ray field, a new nuclear emulsion and its data-processing system are developed. This report examined the optimal development conditions about the new nuclear emulsion NGITA (Neutron-Gamma Image TrAcker). By lowering developing solution temperature to 10 C from 20 C, the sensitivity to a ray was able to be controlled to the abbreviation 1/10, with the sensitivity to a neutron maintained.
Sakai, Yosuke*; Minato, Haruna*; Ishihara, Kohei*; Tomita, Hideki*; Kawarabayashi, Jun*; Iguchi, Tetsuo*; Naka, Tatsuhiro*; Asada, Takashi*; Morishima, Kunihiro*; Nakano, Toshiyuki*; et al.
no journal, ,
In order to measure a neutron-spectrum under high ray environment, a new nuclear emulsion and its data-processing method are developed. In fast neutron measurement using the nuclear emulsion which can record the three-dimensional track of a charged particle, incidence neutron energy spectrum can be obtained by analyzing the track of the recoil proton generated by the elastic scattering of a neutron. The high-speed automatic analytic method of the recoil proton track in a nuclear plate is developed. It checked that the recoil proton track length distribution obtained by viewing and automatic analysis was in agreement with a model calculation result about by the basic experiment using 14 MeV neutron.
Sakai, Yosuke*; Minato, Haruna*; Ishihara, Kohei*; Tomita, Hideki*; Kawarabayashi, Jun*; Iguchi, Tetsuo*; Naka, Tatsuhiro*; Asada, Takashi*; Morishima, Kunihiro*; Nakano, Toshiyuki*; et al.
no journal, ,
In order to measure a neutron-spectrum under high ray environment, a new nuclear emulsion and its data-processing method are developed. In fast neutron measurement using the nuclear emulsion which can record the three-dimensional track of a charged particle, incidence neutron energy spectrum can be obtained by analyzing the track of the recoil proton generated by the elastic scattering of a neutron. The high-speed automatic analytic method of the recoil proton track in a nuclear plate is developed. It checked that the recoil proton track length distribution obtained by viewing and automatic analysis was in agreement with a model calculation result about by the basic experiment using 14 MeV neutron.
